From: "David Schwartz" <davids@webmaster.com>
To: "Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>
Subject: RE: [patch] spinlocks: remove 'volatile'
Date: Sun, 9 Jul 2006 12:16:15 -0700 [thread overview]
Message-ID: <MDEHLPKNGKAHNMBLJOLKMEPGNAAB.davids@webmaster.com> (raw)
In-Reply-To: <44B0FAD5.7050002@argo.co.il>
> Volatile is useful for non device driver work, for example VJ-style
> channels. A portable volatile can help to code such things in a
> compiler-neutral and platform-neutral way. Linux doesn't care about
> compiler neutrality, being coded in GNU C, and about platform
> neutrality, having a per-arch abstraction layer, but other programs may
> wish to run on multiple compilers and multiple platforms without
> per-platform glue layers.
There is a portable volatile, it's called 'pthread_mutex_lock'. It allows
you to code such things in a compiler-neutral and platform-neutral way. You
don't have to worry about what the compiler might do, what the hardware
might do, what atomic operations the CPU supports, or anything like that.
The atomicity issues I've mentioned in my other posts make any attempt at
creating a 'portable volatile' for shared memory more or less doomed from
the start.
DS
next prev parent reply other threads:[~2006-07-09 19:16 UTC|newest]
Thread overview: 163+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-05 8:49 [patch] uninline init_waitqueue_*() functions Ingo Molnar
2006-07-05 9:31 ` Andrew Morton
2006-07-05 9:32 ` Ingo Molnar
2006-07-05 9:53 ` Andrew Morton
2006-07-05 10:26 ` Ingo Molnar
2006-07-05 11:30 ` Ingo Molnar
2006-07-05 11:46 ` Ingo Molnar
2006-07-05 17:10 ` Andrew Morton
2006-07-05 19:35 ` Ingo Molnar
2006-07-05 20:18 ` Andrew Morton
2006-07-05 20:36 ` Linus Torvalds
2006-07-05 20:47 ` Ingo Molnar
2006-07-05 21:15 ` Ingo Molnar
2006-07-05 21:21 ` Linus Torvalds
2006-07-05 21:45 ` Ingo Molnar
2006-07-05 21:58 ` Randy.Dunlap
2006-07-05 22:00 ` Ingo Molnar
2006-07-05 22:10 ` Randy.Dunlap
2006-07-05 22:27 ` Ingo Molnar
2006-07-05 23:15 ` Adrian Bunk
2006-07-05 22:09 ` Linus Torvalds
2006-07-05 22:30 ` Ingo Molnar
2006-07-05 23:11 ` Linus Torvalds
2006-07-06 8:16 ` [patch] spinlocks: remove 'volatile' Ingo Molnar
2006-07-06 8:23 ` Ingo Molnar
2006-07-06 9:27 ` Heiko Carstens
2006-07-06 9:34 ` Arjan van de Ven
2006-07-06 11:59 ` linux-os (Dick Johnson)
2006-07-06 12:01 ` Arjan van de Ven
2006-07-06 12:29 ` linux-os (Dick Johnson)
2006-07-06 12:39 ` Arjan van de Ven
2006-07-06 13:39 ` J.A. Magallón
2006-07-06 13:43 ` Arjan van de Ven
2006-07-06 14:05 ` Chase Venters
2006-07-06 14:26 ` Andreas Schwab
2006-07-06 16:40 ` Nick Piggin
2006-07-06 23:19 ` David Schwartz
2006-07-06 18:15 ` Mark Lord
2006-07-06 19:15 ` Linus Torvalds
2006-07-06 19:33 ` Chris Friesen
2006-07-06 19:37 ` Mark Lord
2006-07-06 20:28 ` Chris Friesen
2006-07-06 20:32 ` Linus Torvalds
2006-07-06 19:38 ` Arjan van de Ven
2006-07-06 19:41 ` Måns Rullgård
2006-07-06 19:42 ` Jeff Garzik
2006-07-06 19:58 ` Linus Torvalds
2006-07-06 20:27 ` Mark Lord
2006-07-06 20:40 ` Chris Friesen
2006-07-06 21:00 ` Linus Torvalds
2006-07-08 8:40 ` Avi Kivity
2006-07-08 8:51 ` Arjan van de Ven
2006-07-08 9:20 ` Avi Kivity
2006-07-08 9:51 ` Arjan van de Ven
2006-07-08 10:18 ` Avi Kivity
2006-07-08 10:28 ` Thomas Gleixner
2006-07-09 4:19 ` Benjamin Herrenschmidt
2006-07-09 12:47 ` Avi Kivity
2006-07-09 19:16 ` David Schwartz [this message]
2006-07-09 19:51 ` Theodore Tso
2006-07-09 20:40 ` [OT] 'volatile' in userspace Rutger Nijlunsing
2006-07-10 3:42 ` Theodore Tso
2006-07-10 17:00 ` Joshua Hudson
2006-07-10 17:54 ` Nick Piggin
2006-07-11 7:48 ` Jan Engelhardt
2006-07-11 11:53 ` Nick Piggin
2006-07-11 19:09 ` Björn Steinbrink
2006-07-11 20:55 ` Jeff Dike
2006-07-10 18:54 ` Jeff Dike
2006-07-10 20:09 ` Philippe Troin
2006-07-10 20:52 ` Jeff Dike
2006-07-06 16:07 ` [patch] spinlocks: remove 'volatile' Linus Torvalds
2006-07-06 16:13 ` Linus Torvalds
2006-07-06 17:04 ` Jeff Garzik
2006-07-06 17:52 ` linux-os (Dick Johnson)
2006-07-06 18:00 ` Linus Torvalds
2006-07-06 21:02 ` J.A. Magallón
2006-07-06 21:12 ` Linus Torvalds
2006-07-06 18:10 ` Michael Buesch
2006-07-06 18:16 ` Chase Venters
2006-07-07 18:16 ` Krzysztof Halasa
2006-07-07 19:51 ` linux-os (Dick Johnson)
2006-07-07 20:25 ` Linus Torvalds
2006-07-07 21:22 ` linux-os (Dick Johnson)
2006-07-07 21:48 ` Chase Venters
2006-07-08 10:00 ` Krzysztof Halasa
2006-07-08 13:41 ` Chase Venters
2006-07-08 20:09 ` Krzysztof Halasa
2006-07-08 20:40 ` Chase Venters
2006-07-08 20:47 ` Chase Venters
2006-07-09 10:57 ` Krzysztof Halasa
2006-07-07 21:59 ` Linus Torvalds
2006-07-07 22:06 ` Linus Torvalds
2006-07-08 20:49 ` Pavel Machek
2006-07-08 21:43 ` Linus Torvalds
2006-07-07 22:05 ` J.A. Magallón
2006-07-07 22:22 ` Chase Venters
2006-07-07 22:37 ` J.A. Magallón
2006-07-08 9:33 ` David Schwartz
2006-07-07 22:49 ` J.A. Magallón
2006-07-07 22:59 ` Vadim Lobanov
2006-07-07 23:18 ` Chase Venters
2006-07-07 23:36 ` Davide Libenzi
2006-07-07 22:09 ` Ingo Molnar
2006-07-08 7:36 ` Ingo Molnar
2006-07-07 20:39 ` Krzysztof Halasa
2006-07-07 23:06 ` Björn Steinbrink
2006-07-08 8:36 ` Avi Kivity
2006-07-06 19:32 ` Jan Engelhardt
2006-07-06 20:26 ` Jeremy Fitzhardinge
2006-07-06 20:55 ` Jan Engelhardt
2006-07-06 21:07 ` Linus Torvalds
2006-07-06 19:56 ` Linus Torvalds
2006-07-06 20:34 ` Linus Torvalds
2006-07-08 22:50 ` Ralf Baechle
2006-07-09 3:09 ` Linus Torvalds
2006-07-09 3:07 ` Keith Owens
2006-07-09 3:29 ` Linus Torvalds
2006-07-09 3:43 ` Keith Owens
2006-07-09 3:58 ` Linus Torvalds
2006-07-09 6:13 ` David Miller
2006-07-09 14:28 ` Roman Zippel
2006-07-09 15:27 ` Linus Torvalds
2006-07-06 8:18 ` [patch] lockdep: clean up completion initializer in smpboot.c Ingo Molnar
2006-07-06 8:23 ` [patch] uninline init_waitqueue_*() functions Ingo Molnar
2006-07-06 9:02 ` Andrew Morton
2006-07-06 9:12 ` [patch] uninline init_waitqueue_head() Ingo Molnar
2006-07-05 20:45 ` [patch] uninline init_waitqueue_*() functions Ingo Molnar
2006-07-05 10:37 ` Christoph Hellwig
2006-07-05 10:44 ` Andrew Morton
2006-07-05 10:46 ` Andrew Morton
2006-07-05 10:47 ` Ingo Molnar
2006-07-05 9:54 ` [patch] uninline init_waitqueue_*() functions, fix Ingo Molnar
2006-07-07 10:21 [patch] spinlocks: remove 'volatile' Chuck Ebbert
2006-07-07 17:09 ` Linus Torvalds
2006-07-08 3:54 Albert Cahalan
2006-07-08 5:25 ` Linus Torvalds
2006-07-08 6:39 ` Nick Piggin
2006-07-08 18:53 ` Linus Torvalds
2006-07-08 9:45 ` Joe Korty
2006-07-08 9:52 ` Arjan van de Ven
2006-07-08 9:59 ` David Schwartz
2006-07-08 10:24 ` Thomas Gleixner
2006-07-08 15:49 ` Albert Cahalan
2006-07-08 18:31 ` Thomas Gleixner
2006-07-08 19:33 ` Albert Cahalan
2006-07-08 20:11 ` Linus Torvalds
2006-07-09 21:10 ` Pavel Machek
2006-07-09 22:18 ` Linus Torvalds
2006-07-10 16:25 ` marty fouts
2006-07-08 23:10 ` David Schwartz
2006-07-08 13:57 ` Andi Kleen
2006-07-08 19:13 ` Linus Torvalds
2006-07-08 10:45 ` Krzysztof Halasa
2006-07-08 6:12 trajce nedev
2006-07-08 6:19 ` Chase Venters
2006-07-08 6:45 ` trajce nedev
2006-07-08 6:58 ` Arjan van de Ven
2006-07-08 7:02 ` Vadim Lobanov
2006-07-08 13:46 ` Chase Venters
2006-07-09 4:39 ` Benjamin Herrenschmidt
2006-07-14 3:30 ` Steven Rostedt
2006-07-08 18:23 ` Linus Torvalds
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